A worker cleans the scene inside St. Mark Cathedral – Egypt’s main Coptic Christian cathedral – in central Cairo, following a bombing the killed dozens, Sunday, Dec. 11, 2016.

An ISIS affiliate in Egypt has released a new video showing the suicide bomber who attacked a church in December and vowing more attacks on the country’s Christian minority.

The 20-minute video, which emerged Monday, said Christians were the extremist group’s “favorite prey.”

It showed footage of Abu Abdullah al-Masri, who killed nearly 30 people, mainly women, when he attacked a Cairo church in December. The narrator says the attack was “only the beginning.”

Egypt’s Coptic Christians, who make up around 10 percent of the population, have been increasingly targeted by Muslim extremists, since the 2013 military overthrow of an Islamist president.